Remote control of pivotable stereoscopic camera

ABSTRACT

A camera device and a display device are configured to enable changing direction of capturing a stereoscopic image using a camera pair, according to an operator&#39;s motion. The camera device includes a rotatable camera base on which the stereoscopic camera pair is mounted, a motor configured to rotate the camera base, and a communication interface arranged to receive a movement signal corresponding to the operator&#39;s motion. The display device transmits the movement signal to enable the camera device to align the image capture direction with the operator view, receives stereoscopic images covering more than the operator view from the camera device, and displays a sector of the stereoscopic images corresponding to the operator view.

TECHNICAL FIELD

The invention relates to stereoscopic imaging and more particularly tocamera devices, a method, a computer program and a computer programproduct for controlling a camera device comprising a stereoscopic camerapair and corresponding display device.

BACKGROUND

Remote controlled stereoscopic camera devices are widely used foradvanced remote control of equipment (e.g. robots, surgical systems,etc.) and surveillance.

The stereoscopic camera device comprises two cameras, displacedhorizontally from one another, which are used to obtain two differentviews on a scene. The images from the two cameras are shown torespective eyes of a remote operator using a display device to create animpression of depth, i.e. a 3D image. When the operator turns his/herhead, the cameras should also rotate to observe the scene from adifferent direction.

The time between detecting movement of a head of the operator andshowing scene from right direction is called latency. The latency timehas three main contributions: image processing delay, motor reactiontime and network latency.

High latency destroys immersion effect for the operator, whereby manystereoscopic systems have a strong emphasis on achieving low latency.Image processing delay can be reduced by using light weight encodingalgorithms or by increasing computational power of encoding hardware.Stronger motors are used to combat motor reaction time. Network latencyis kept low by keeping operator relatively close to the cameras.

SUMMARY

According to a first aspect, it is provided a camera device comprising:a rotatable camera base; a motor connected to the camera base; a firstcamera and a second camera forming a first stereoscopic camera pair witha first image capture direction, the first camera and the second cameraboth being wide angle cameras and being mounted on the camera base; acommunication interface arranged to receive a movement signal. Thecamera device is arranged to rotate the camera base based on themovement signal.

The camera device may further comprise: a processor connected to thecommunication interface and the motor; and a memory storing instructionsthat, when executed by the processor, causes the camera device to:receive the movement signal; control the motor to rotate the camera basebased on the movement signal.

The first camera and the second camera may be further arranged totransmit images over the communication interface.

The movement signal may comprise an absolute angle and the camera devicemay be arranged to rotate the camera base by controlling the motor toalign the first image capture direction to correspond to the absoluteangle.

The movement signal may comprise a movement angle and the camera devicemay be arranged to rotate the camera base by controlling the motor torotate the camera base an amount which corresponds to the movementangle.

Each one of the first camera and the second camera may provide asufficiently wide angle image that an operator only views a subset of aresulting image at a time.

The camera device may further comprise a third camera and a fourthcamera forming a second stereoscopic camera pair with a second imagecapture direction, the third camera and the fourth camera being mountedon the camera base. The movement signal then comprises an absolute angleand the camera device is arranged to rotate the camera base to select astereoscopic camera pair having an image capture direction which isnearest to the absolute angle. Moreover, the camera device is arrangedto control the motor to align the image capture direction of theselected stereoscopic camera pair with the absolute angle.

According to a second aspect, it is provided a method for controlling acamera device comprising a rotatable camera base, a motor connected tothe camera base, a first camera and a second camera forming a firststereoscopic camera pair with a first image capture direction, the firstcamera and the second camera both being wide angle cameras and beingmounted on the camera base, and a communication interface. The method isperformed in the camera device and comprises the steps of: receiving amovement signal; controlling the motor to rotate the camera base basedon the movement signal.

The method may further comprise the step of: transmitting images fromthe first camera and the second camera over the communication interface.

The movement signal may comprise an absolute angle and the step ofcontrolling the motor may comprise controlling the motor to align thefirst image capture direction to correspond to the absolute angle.

The movement signal may comprises a movement angle and the step ofcontrolling the motor may comprises controlling the motor to rotate thecamera base an amount which corresponds to the movement angle.

Each one of the first camera and the second camera may provide asufficiently wide angle image that an operator only views a subset of aresulting image at a time.

The camera device may further comprise a third camera and a fourthcamera forming a second stereoscopic camera pair with a second imagecapture direction, the third camera and the fourth camera both beingwide angle cameras and being mounted on the camera base. The movementsignal then comprises an absolute angle and the method further comprisesthe step of: selecting a stereoscopic camera pair having an imagecapture direction which is nearest to the absolute angle. Furthermore,the step of controlling the motor then comprises controlling the motorto align the image capture direction of the selected stereoscopic camerapair with the absolute angle.

According to a third aspect, it is provided a camera device comprising:means for receiving a movement signal over a communication interface;means for controlling the motor to rotate a camera base of the cameradevice based on the movement signal, the camera base having mounted afirst camera and a second camera forming a first stereoscopic camerapair with a first image capture direction, wherein both the first cameraand the second camera are wide angle cameras.

According to a fourth aspect, it is provided a computer program forcontrolling a camera device comprising a rotatable camera base, a motorconnected to the camera base, a first camera and a second camera forminga first stereoscopic camera pair with a first image capture direction,the first camera and the second camera both being wide angle cameras andbeing mounted on the camera base, and a communication interface. Thecomputer program comprising computer program code which, when run on thecamera device causes the camera device to: receive a movement signal;control the motor to rotate the camera base based on the movementsignal.

According to a fifth aspect, it is provided a computer program productcomprising a computer program according to the fourth aspect and acomputer readable means on which the computer program is stored.

According to a sixth aspect, it is provided a display device comprising:a processor; and a memory storing instructions that, when executed bythe processor, causes the display device to: receive stereoscopic imagesfrom a camera device, the stereoscopic images covering more than anoperator view; detect a centre direction of the operator view; display asector of the stereoscopic images on a display of the display device,the centre direction of the sector corresponding to a centre directionof the operator view; and transmit a movement signal to the cameradevice in order to align an image capture direction to the new centredirection of the operator view.

The instructions to transmit a movement signal may comprise instructionsthat, when executed by the processor, causes the display device to onlytransmit the movement signal is when a significant movement of thecentre direction of the operator view is detected.

The display device may further comprise instructions that, when executedby the processor, causes the display device to repeat the mentionedinstructions.

The instructions to detect a new centre direction may compriseinstructions that, when executed by the processor, causes the displaydevice to use a sensor to detect a head movement of an operator.

According to a seventh aspect, it is provided a display devicecomprising: means for receiving stereoscopic images from a cameradevice, the stereoscopic images covering more than an operator view;means for detecting a new centre direction of the operator view; meansfor displaying a sector of the stereoscopic images on a display of thedisplay device, the centre direction of the sector corresponding to acentre direction of the operator view; and means for transmitting amovement signal to the camera device in order to align an image capturedirection to the new centre direction of the operator view.

According to an eighth aspect, it is provided a method for showingstereoscopic images. The method is performed in a display device andcomprises the steps of: receiving stereoscopic images from a cameradevice, the stereoscopic images covering more than an operator view;detecting a centre direction of the operator view; displaying a sectorof the stereoscopic images on a display of the display device, thecentre direction of the sector corresponding to a centre direction ofthe operator view; and transmitting a movement signal to the cameradevice in order to align an image capture direction to the centredirection of the operator view.

The step of transmitting a movement signal is in one embodiment onlyperformed when a significant movement of the centre direction of theoperator view is detected.

The method may be repeated.

The step of detecting a new centre direction may comprise using a sensorto detect a head movement of an operator.

According to a ninth aspect, it is provided a computer program forshowing stereoscopic images. The computer program comprises computerprogram code which, when run on a display device causes the displaydevice to: receive stereoscopic images from a camera device, thestereoscopic images covering more than an operator view; detect a newcentre direction of the operator view; display a sector of thestereoscopic images on a display of the display device, the centredirection of the sector corresponding to a centre direction of theoperator view; and transmit a movement signal to the camera device inorder to align an image capture direction to the new centre direction ofthe operator view.

According to a tenth aspect, it is provided a computer program productcomprising a computer program according to the ninth aspect and acomputer readable means on which the computer program is stored.

Using the solution of the camera device providing a wide angle image,the display device can respond to many operator movements virtuallywithout latency, as long as the movement is within the scope of the wideangle image, thus requiring no new communication with the camera devicefor this initial adjustment. While this temporarily reduces depth, thisis quickly remedied since the camera device commands the camera deviceto align to the new direction of the operator. This provides a greatbalance between immersion (due to the immediate response) and depth (dueto the movement of the camera device.

Generally, all terms used in the claims are to be interpreted accordingto their ordinary meaning in the technical field, unless explicitlydefined otherwise herein. All references to “a/an/the element,apparatus, component, means, step, etc.” are to be interpreted openly asreferring to at least one instance of the element, apparatus, component,means, step, etc., unless explicitly stated otherwise. The steps of anymethod disclosed herein do not have to be performed in the exact orderdisclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, by way of example, with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic diagram showing some components of a camera deviceand a display device;

FIG. 2 is a schematic diagram illustrating a camera device according toone embodiment;

FIG. 3 is a schematic diagram illustrating a camera device according toone embodiment;

FIGS. 4A-C are schematic diagrams illustrating embodiments of how acamera device of FIG. 2 or FIG. 3 is controlled based on a movementsignal;

FIGS. 5A-B are flow charts illustrating methods performed in the cameradevice of FIG. 1 or 2 for controlling the camera device;

FIG. 6 is a flow chart illustrating a method performed in the displaydevice of FIG. 1 for showing stereoscopic images according to oneembodiment;

FIG. 7 is a schematic diagram showing functional modules of the cameradevice of FIG. 1 or 2; and

FIG. 8 is a schematic diagram showing functional modules of the displaydevice of FIG. 1; and

FIG. 9 shows one example of a computer program product comprisingcomputer readable means.

DETAILED DESCRIPTION

The invention will now be described more fully hereinafter withreference to the accompanying drawings, in which certain embodiments ofthe invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided byway of example so that this disclosure will be thorough and complete,and will fully convey the scope of the invention to those skilled in theart. Like numbers refer to like elements throughout the description.

FIG. 1 is a schematic diagram showing some components of a camera device1 and a display device 20. The camera device 1 comprises a rotatablecamera base 3 and a motor 5 connected to the camera base 3. A firstcamera 6 a and a second camera 6 b are mounted with a horizontaldisplacement on the camera base 3. The first camera 6 a and the secondcamera 6 b together form a stereoscopic camera pair 10, allowing threedimensional (3D) image capture. The camera base 3 is any suitablestructure suitable for mounting the camera devices 6 a-b upon and whichcan be controlled by the motor 5 to rotate. The motor 5 is any suitablemotor capable of rotating the camera base 3 to a suitable direction. Forexample, the motor 5 can be an electrical motor such as a DC (directcurrent) motor, e.g. a stepper motor.

A communication (Input/Output) interface 57 is provided to allowcommunication with the display device 20 using wireless or wiredcommunication, e.g. over an Internet Protocol (IP) network. In this way,the camera device can transmit images 31 from the cameras 6 a-b to thedisplay device 20. Also, this allows the camera device 1 to receivemovement signals 30 or other commands from the display device 20.

An optional processor 50 is provided using any combination of one ormore of a suitable central processing unit (CPU), multiprocessor,microcontroller, digital signal processor (DSP), etc., capable ofexecuting software instructions 58 stored in a memory 54, which can thusbe a computer program product. The processor 50 can be configured toexecute the method described with reference to FIGS. 5A-B below. Theprocessor 50 is connected to the motor 5, the cameras 6 a-b, thecommunication interface 57, the memory 54 and a data memory 59.

Alternatively, the method described with reference to FIGS. 5A-B belowcan be performed in the camera device without using software, i.e. usinghardware, such as an Application Specific Integrated Circuit (ASIC) ordiscrete digital and/or analogue components. Also, hardware processingand software processing can be mixed.

The memory 54 can be any combination of read and write memory (RAM) andread only memory (ROM). The memory 54 also comprises persistent storage,which, for example, can be any single one or combination of magneticmemory, optical memory, solid state memory or even remotely mountedmemory.

The data memory 59 is also provided for reading and/or storing dataduring execution of software instructions in the processor 50. The datamemory 59 can be any combination of read and write memory (RAM) and readonly memory (ROM).

Other components of the camera device 1 are omitted in order not toobscure the concepts presented herein.

The display device 20 comprises its own communication (Input/Output)interface 67 that is provided to allow communication with the cameradevice 1, e.g. for transmitting movement signals 30 and receiving images31.

A processor 60 is provided using any combination of one or more of asuitable central processing unit (CPU), multiprocessor, microcontroller,digital signal processor (DSP), application specific integrated circuitetc., capable of executing software instructions 68 stored in a memory64, which can thus be a computer program product. The processor 60 canbe configured to execute the method described with reference to FIG. 6below. The processor 60 is connected to the communication interface 67,the memory 64, a data memory 69 a 3D display 61 and an optionaldirectional sensor 65. The sensor 65 can detect a direction of anoperator, e.g. by sensing a rotation of a head of an operator bymounting the sensor 65 to the head or otherwise detecting head rotationof the operator.

The memory 64 can be any combination of read and write memory (RAM) andread only memory (ROM). The memory 64 also comprises persistent storage,which, for example, can be any single one or combination of magneticmemory, optical memory, solid state memory or even remotely mountedmemory.

The data memory 69 is also provided for reading and/or storing dataduring execution of software instructions in the processor 60. The datamemory 69 can be any combination of read and write memory (RAM) and readonly memory (ROM).

A 3D display 61 is provided connected to the CPU 60. The 3D display 61can be part of the display device 20 or external to the display device20, such as in an operator worn device. The 3D display 61 is capable ofproviding two stereoscopic images to provide a three dimensional imageto a viewer of the 3D display 61. This can be provided using anyexisting or future 3D display technology, e.g. separate physical smalldisplays for each eye, polarized images, temporal switched images, etc.Polarized images and switched images may require an operator to wearappropriate 3D glasses.

Other components of the display device 20 are omitted in order not toobscure the concepts presented herein.

In this way, images captured by the stereoscopic camera pair of thecamera device are provided to the 3D display 61 of the display device20. This allows an operator at the display device to experience 3Dimages of the remote location of the camera device 1.

Both the first camera and the second camera are wide angle cameras,providing a sufficiently wide angle image such that an operator onlyviews an operator view being a subset of a resulting image at a time.

Since impression of depth is proportional to effective distance betweentwo cameras it is not sufficient to place cameras statically in order toachieve 3D vision in all direction. The operator gets full impression ofdepth only in direction which is close to the image capture direction.

But here the two wide angle cameras 6 a-b are placed on the rotatablecamera base 3. Once the operator turns his or her head, (by X radians)this is sensed by the sensor 65 and the picture corresponding to the newdirection is shown to him virtually immediately (X radians from thecentral direction), as long as this can be achieved using the wide angleimages from the cameras 6 a-b which are currently present in the displaydevice 20. If the angle X is relatively large, the 3D picture might lacksome depth in it. However, the sensor noticing the new direction alsotriggers the processor 60 to transmit a movement signal 30 to the cameradevice 1 to rotate the camera base 3 accordingly. While the camera base3 is rotating, the operator view, being the section of the picture shownto the operator, also rotates in an opposite direction, to cancel outthe rotation of the cameras. The centre direction of the operator viewdoes not change, since the rotation actually occurs after the head turn.Once the cameras have turned completely, the operator once againobserves a deep 3D picture of the scene.

In this way, when the operator makes a sharp head turn and stops in thenew direction, he/she more or less instantly gets a picture from thisdirection (may be somewhat flat at first). Over time the direction ofview stays the same for him (in case the head is not turned more) butthe picture becomes gradually deeper as the cameras turn.

This provides an immersive 3D vision system for an operator, even whenthe latency would otherwise prevent such immersion.

Accordingly, the latency in the system will impact only how fastoperator gets the fully deep picture with sharp head turning. With smallhead movement, the lost depth will be unnoticeable. For humans it takessome time to re-focus once we change direction of view, whereby temporalloss of depth after sharp head turn should not have major impact onimmersive 3D feeling experienced by operator. Optionally, the cameradevice transmits a lower resolution image while the camera base 3 is inmotion, since there is a delay to the eye adjustment anyway, therebyreducing bandwidth usage.

Moreover, the operator at the display device 20 can send a movementsignal 30 (over the communication link) to the camera device 1 to rotateto alter its view. The camera device effects this by rotating the camerabase 3, to thereby direct the stereoscopic camera pair to a new angle.

FIG. 2 is a schematic diagram illustrating a camera device according toone embodiment.

The camera base 3 of the camera device 1 is now seen from above and isrotatable around a coordinate system having its origin aligned with theaxis of rotation of the camera base 3. A first stereoscopic camera pair10 a comprises a first camera 6 a and the second camera 6 b. The firststereoscopic camera pair 10 a has a first image capture direction 11 awhich is defined in relation to the coordinate system. The first imagecapture direction 11 a can be defined as the mean of the centerdirections of the two cameras 6 a-b of the first stereoscopic camerapair. For instance, in an example where the center directions of the twocameras 6 a-b are aligned, then the first image capture direction 11 ais also aligned to this direction.

The first camera 6 a has a first viewing angle 12 a and the secondcamera 6 b has a second viewing angle 12 b. A first object 15 a iswithin view of both cameras 6 a-b. A second object is also within viewof both cameras 6 a-b. A third object 15 c, however, is out of view forboth cameras 6 a-b.

If an operator of the display device 20 connected to the camera devicewants to see the third object 15 c, a movement signal is sent to thecamera device to rotate the camera base so that the cameras can captureimages comprising the third object 15 c, as shown in FIGS. 4A-B andexplained in more detail below.

In FIG. 3, compared to FIG. 2, the camera device 1 comprises is a secondstereoscopic camera pair bob comprising a third camera 6 c and a fourthcamera 6 d. The second stereoscopic camera pair 10 b has a second imagecapture direction 11 b which is also defined in relation to thecoordinate system. The second image capture direction 11 b is definedanalogously with the first image capture direction 11 a.

The camera device 1 may comprise further camera pairs to further reduceany required movement angle and/or increase static viewing angles of thecamera device 1.

The operation of this embodiment is shown in FIG. 4C and explained inmore detail below.

FIGS. 4A-B are schematic diagrams illustrating embodiments of how thecamera device of FIG. 2 or 3 is controlled based on a movement signal.

In FIG. 4A, the movement signal comprises an absolute angle 14. Absoluteangle is here to be construed as a non-relative angle. In other words,the absolute angle could be positive or negative. The camera device 1then needs to align the first image capture direction 11 a with theabsolute angle 14 by rotating the camera base 3 with a differentialangle 17. The differential angle is calculated as the difference betweenthe first image capture direction 11 a and the absolute angle 14. Thedifferential angle 17 can be positive (implying anticlockwise rotation)or negative (implying clockwise rotation), whichever direction resultsin the shortest magnitude of the rotation angle. In this example, thedifferential angle is negative whereby the rotation is clockwise.

In FIG. 4B, the movement signal comprises a movement angle 16. This is arelative signal, whereby the camera device 1 controls the motor torotate the camera base 3 with an amount which corresponds to themovement angle 16. The movement angle can be positive, resulting in ananticlockwise rotation, or negative, resulting in a clockwise rotation.In this example, the movement angle 16 is positive, resulting in aclockwise rotation.

In FIG. 4C, the camera device 1 comprises both a first stereoscopiccamera pair 10 a and a second stereoscopic camera pair 10 b. In thisway, when the display device sends a movement signal with an absolutedirection, the camera device 1 selects the stereoscopic camera pairhaving an image capture direction which is nearest to the absolute angle14. In this example, the second image capture direction 11 b of thesecond stereoscopic camera pair 10 b is closest to the absolute angle14. The camera device 1 then controls the motor to align the imagecapture direction of the selected stereoscopic camera pair with theabsolute angle 14. This is achieved by calculating a differential angle17 between image capture direction of the selected stereoscopic pair andthe absolute angle 14 and controlling a rotation of the camera base 3 inaccordance with the differential angle 17.

In one embodiment, the camera device 1 transmits images captured fromall cameras to the display device 20, whereby the display device canprocess and select what images should be shown on the 3D display.

In one embodiment, the camera device only transmits images from thestereoscopic camera pair which is active at the moment, which reducesthe bandwidth requirements for the images 31 transmitted to the displaydevice.

In one embodiment, the stereoscopic camera pair is only allowed toswitch if the velocity of desired rotation is fast enough.

FIGS. 5A-B are flow charts illustrating methods performed in the cameradevice of FIG. 1, FIG. 2 or FIG. 3 for controlling the camera device.

In a receive movement signal step 40, a movement signal 30 is receivedfrom the display device 20. The movement signal 30 instructs the cameradevice to rotate the camera base upon which the cameras are mounted.

In one embodiment, the movement signal 30 comprises an absolute angle14, i.e. instructing the camera device to align its view to the absoluteangle 14.

In one embodiment, the movement signal 30 comprises a movement angle,which is a relative movement command, e.g. move x radians (or degrees),where x is a positive or negative number.

In a control motor step 42, the motor 5 is controlled to rotate thecamera base 3 based on the movement signal 30.

When the movement signal 30 comprises an absolute angle 14, this stepcomprises controlling the motor to align the first image capturedirection 11 a to correspond to the absolute angle 14.

When the movement signal 30 comprises a movement angle, this stepcomprises controlling the motor to rotate the camera base an amountwhich corresponds to the movement angle.

FIG. 5B is a flow chart illustrating a method similar to the methodillustrated in FIG. 5A. Only new or modified steps in relation to themethod of FIG. 5A are explained here.

In an optional select camera pair step 41, a stereoscopic camera pair isselected which has an image capture direction which is nearest to theabsolute angle. This step is only performed when the movement signalcomprises an absolute angle, and the camera device comprises at leasttwo stereoscopic camera pairs.

When the select camera pair step 41 is performed, the control motor step42 comprises controlling the motor to align the image capture directionof the selected stereoscopic camera pair with the absolute angle.

In an optional transmit images step 44, images from the first camera 6 aand the second camera 6 b are transmitted over the communicationinterface 57, e.g. to the display device. Alternatively or additionally,images from another stereoscopic camera pair are also transmitted overthe communication interface.

FIG. 6 is a flow chart illustrating a method performed in the displaydevice of FIG. 1 for showing stereoscopic images according to oneembodiment.

In a receive step 70, stereoscopic images are received from the cameradevice. The stereoscopic images cover more than an operator view. It isalso here received the image capture direction of the stereoscopicimages.

In a detect step 74, a new centre direction of the operator view isdetected. This can e.g. be performed using the sensor 65 to detect ahead movement of an operator.

In a display step 75, a sector of the last received stereoscopic imagesis displayed on the display 61 of the display device 20. The centredirection of the sector corresponds to a centre direction of theoperator view. It is to be noted that the sector is a strict subset ofthe complete stereoscopic images. This step involves displaying twoimages on the 3D display 61.

In a conditional significant movement step 76, it is determined whethera significant movement of the centre direction of the operator view isdetected. For instance, this can involve comparing the centre directionof the operator view of different iterations of the detect step.Alternatively or additionally, a significant movement is detected whenthe sector is closer to the border of the stereoscopic images than athreshold amount. Alternatively or additionally, a significant movementis detected when the centre direction of the sector deviates more than athreshold amount from the image capture direction. If there issignificant movement, the method proceeds to a transmit movement signalstep 78, otherwise, the method proceeds to a conditional new imageavailable step 79.

In the transmit movement signal step 78, the movement signal istransmitted to the camera device 1 in order to align an image capturedirection to the new centre direction of the operator view. As explainedabove, the movement signal can comprise an absolute angle or movementangle depending on how much processing the camera device 1 shouldperform.

After the transmit movement signal step, the method proceeds to theconditional new image available step 79.

In the conditional new image available step 79, it is determined whetherthere is a new stereoscopic image to be received. It is to be noted thatthe stereoscopic images can be received as a sequence of individualimages or as a media stream. In either case, it is here determinedwhether a new stereoscopic image is ready to be received. If this is thecase, the method returns to the receive step 70, otherwise, the methodreturns to the detect step 74 to continue dynamic tracking of operatormovement.

FIG. 7 is a schematic diagram showing functional modules of the cameradevice 1 of FIG. 2 or 3. The modules are implemented using softwareinstructions such as a computer program executing in the camera device1. The modules correspond to the steps in the methods illustrated inFIGS. 5A-B.

A receiver 80 is arranged to receive a movement signal. This modulecorresponds to the receive movement signal 40 of FIGS. 5A-B.

A selector 82 is arranged to select the stereoscopic camera pair havingan image capture direction which is nearest to an absolute angle whenpresent in the movement signal. This module corresponds to the selectcamera pair step 41 of FIG. 5B.

A controller 84 is arranged to control the motor to rotate the camerabase based on the movement signal. This module corresponds to thecontrol motor step 42 of FIGS. 5A-B.

A transmitter 86 is arranged to transmit images from cameras of at leastone stereoscopic camera pair to the display device. This modulecorresponds to the transmit images step 44 of FIG. 5B.

FIG. 8 is a schematic diagram showing functional modules of the displaydevice of FIG. 1. The modules are implemented using softwareinstructions such as a computer program executing in the display device20. The modules correspond to the steps in the methods illustrated inFIG. 6.

A receiver 92 is arranged to receive stereoscopic images from a cameradevice. This module corresponds to the receive step of FIG. 6.

A displayer 93 is arranged to display a sector of the stereoscopicimages on a display of the display device, the centre direction of thesector corresponding to a centre direction of the operator view. Thismodule corresponds to the display step of FIG. 6.

A detector 94 is arranged to detect a centre direction of the operatorview. This module corresponds to the detect step of FIG. 6.

A transmitter 96 is arranged to transmit a movement signal to the cameradevice in order to align an image capture direction to the new centredirection of the operator view. This module corresponds to the transmitmovement signal step of FIG. 6.

FIG. 9 shows one example of a computer program product comprisingcomputer readable means. On this computer readable means a computerprogram 91 can be stored, which computer program can cause a processorto execute a method according to embodiments described herein. In thisexample, the computer program product is an optical disc, such as a CD(compact disc) or a DVD (digital versatile disc) or a Blu-Ray disc. Asexplained above, the computer program product could also be embodied ina memory of a device, such as the computer program products 54 or 64 ofFIG. 1.

While the computer program 91 is here schematically shown as a track onthe depicted optical disk, the computer program can be stored in any waywhich is suitable for the computer program product, such as a removablesolid state memory (e.g. a Universal Serial Bus (USB) drive).

It is to be noted that while the embodiments presented herein mainlydescribe horizontal movement, the same principles shown herein canequally well be applied to vertical movement as an alternative or inaddition to horizontal movement.

The invention has mainly been described above with reference to a fewembodiments. However, as is readily appreciated by a person skilled inthe art, other embodiments than the ones disclosed above are equallypossible within the scope of the invention, as defined by the appendedpatent claims.

The invention claimed is:
 1. A camera device comprising: a rotatablecamera base; a motor connected to the camera base; a first camera and asecond camera forming a first stereoscopic camera pair with a firstimage capture direction, the first camera and the second camera bothbeing wide angle cameras and being mounted on the camera base, whereinthe first stereoscopic camera pair captures images that form astereoscopic image covering a wider angle than an operator views at atime; and a communication interface arranged to receive a movementsignal corresponding to the operator's motion away from the first imagecapture direction and towards a new image capture direction; wherein thecamera base is rotated based on the movement signal away from the firstimage capture direction and towards the new image capture direction,wherein when the first stereoscopic camera pair has the first imagecapture direction, the images that form the stereoscopic image are inthe first image capture direction and provide an impression of depth inthe first image capture direction, wherein when the first stereoscopiccamera pair has the new image capture direction, the images that formthe stereoscopic image are in the new image capture direction andprovide the impression of depth in the new image capture direction, andwherein, during at least part of a duration during which the camera baseis rotated based on the movement signal away from the first imagecapture direction and towards the new image capture direction, theimages that form the stereoscopic image are in the new image capturedirection with at least a partial loss of the perception of depth in thenew image capture direction.
 2. The camera device according to claim 1,further comprising: a processor connected to the communication interfaceand the motor; and a memory storing instructions that, when executed bythe processor make the processor: to receive the movement signal; and tocontrol the motor to rotate the camera base.
 3. The camera deviceaccording to claim 1, wherein the first camera and the second camera arefurther configured to transmit images captured by the first stereoscopiccamera pair over the communication interface.
 4. The camera deviceaccording to claim 1, wherein the movement signal comprises an absoluteangle, and wherein the motor rotates the camera base so as to align thefirst image capture direction to correspond to the absolute angle. 5.The camera device according to claim 1, wherein the movement signalcomprises a movement angle and the motor rotates the camera base with anamount which corresponds to the movement angle.
 6. The camera deviceaccording to claim 1, further comprising a third camera and a fourthcamera forming a second stereoscopic camera pair with a second imagecapture direction, the third camera and the fourth camera being mountedon the camera base; wherein the movement signal comprises an absoluteangle and the first or the second stereoscopic camera pair is selecteddepending on whether the first image capture direction or the secondimage capture direction is nearest to the absolute angle; and the motorrotates the camera base to align the first or second image capturedirection of the selected first or second stereoscopic camera pair tocorrespond to the absolute angle.
 7. A method for controlling an imagecapturing direction of a camera device according to an operator'smotion, the camera device including a rotatable camera base, a motorconnected to the camera base, a first camera and a second camera forminga first stereoscopic camera pair with a first image capture direction,the first camera and the second camera both being wide angle cameras andbeing mounted on the camera base, wherein the first stereoscopic camerapair captures images that form a stereoscopic image covering a widerangle than the operator views at a time, and a communication interface,the method comprising: receiving, by the communication interface, amovement signal corresponding to the operator's motion away from thefirst image capture direction and towards a new image capture direction;and controlling the motor to rotate the camera base based on themovement signal away from the first image capture direction and towardsthe new image capture direction, wherein when the first stereoscopiccamera pair has the first image capture direction, the images that formthe stereoscopic image are in the first image capture direction andprovide an impression of depth in the first image capture direction,wherein when the first stereoscopic camera pair has the new imagecapture direction, the images that form the stereoscopic image are inthe new image capture direction and provide the impression of depth inthe new image capture direction, and wherein, during at least part of aduration during which the camera base is rotated based on the movementsignal away from the first image capture direction and towards the newimage capture direction, the images that form the stereoscopic image arein the new image capture direction with at least a partial loss of theperception of depth in the new image capture direction.
 8. The methodaccording to claim 7, further comprising: transmitting images capturedby the first camera and the second camera over the communicationinterface.
 9. The method according to claim 7, wherein the movementsignal comprises an absolute angle and wherein the controlling isperformed to align the first image capture direction to correspond tothe absolute angle.
 10. The method according to claim 7, wherein themovement signal comprises a movement angle and wherein the controllingoperates the motor to rotate the camera base an amount which correspondsto the movement angle.
 11. The method according to claim 7, wherein thecamera device further comprises a third camera and a fourth cameraforming a second stereoscopic camera pair with a second image capturedirection, the third camera and the fourth camera both being wide anglecameras and being mounted on the camera base; the movement signalcomprises an absolute angle, and the method further comprises selectingthe first stereoscopic camera pair or the second stereoscopic camerapair depending on whether the first or the second image capturedirection is nearest to the absolute angle; and wherein the controllingis performed to operate the motor so as to align the first or secondimage capture direction of the selected first or second stereoscopiccamera pair to correspond to the absolute angle.
 12. The methodaccording to claim 7, further comprising: receiving the images that formthe stereoscopic image from the camera device, the stereoscopic imagecovering more than an operator view; detecting a new centre direction ofthe operator view away from the first image capture direction andtowards the new image capture direction; and displaying a sector of thestereoscopic image.
 13. The method according to claim 12, wherein thereceiving of the images that form the stereoscopic image, the detectingthe new centre direction and the displaying of the sector of thestereoscopic image are performed by a display device, which is alsoconfigured to detect the operator's motion and transmits the motionsignal to the camera device.
 14. The method according to claim 7,wherein the motion signal is received when the operator's motion rotatesa minimum amount.
 15. A display device comprising: a processor; adisplay; and a non-transitory computer readable medium storinginstructions that, when executed by the processor make the processor: toreceive stereoscopic images from a camera device, the stereoscopicimages covering more than an operator view; to detect a first centredirection of the operator view and a movement thereof away from thefirst centre direction and towards a new centre direction; to triggerdisplaying a sector of the stereoscopic images on the display so that acentre direction of the sector corresponds to the new centre directionof the operator view; and to transmit a movement signal corresponding toan operator's motion to the camera device to enable the camera device toalign an image capture direction according to the new centre directionof the operator view.
 16. The display device according to claim 15,wherein the movement signal is transmitted only when the movement of thefirst centre direction away from the first centre direction and towardsthe new centre direction is significant as to degrade the operator view.17. The display device according to claim 15, wherein the instructionsmake the processor to receive stereoscopic images, to detect the firstcentre direction and the movement away from the first centre directionand towards the new centre direction, to trigger displaying and totransmit the movement signal repeatedly.
 18. The display deviceaccording to claim 15, wherein the processor detects the motion based onsignals received from a motion sensor configured to detect a headmovement of an operator.